Abstract: A sound processing apparatus includes an inputting section that inputs a sound signal, an analyzing section that analyzes the input sound signal, a storing section that stores a general-purpose masking sound, a masking sound producing section that, based on a result of the analysis by the analyzing section, processes the general-purpose masking sound stored in the storing section to produce an output masking sound, and an outputting section that outputs the output masking sound.

Abstract: A reverberation suppression device includes an analyzer configured to analyze change over time in the power of an input signal obtained from a microphone in response to sound input, and thereby compute the decrease per unit time in the power of the input signal in a reverb segment following the end of a segment in which the sound is produced; and a suppression controller configured to control a suppression gain which indicates the rate at which the input signal is attenuated, on the basis of analysis results from the analyzer.

Abstract: An ANC apparatus using so-called adaptive control is provided with a cancellation sound output means which outputs front wheel cancellation sound that cancels front wheel vibration noise due to front wheel vibration at a position to be silenced on the basis of a front wheel reference signal, and outputs rear wheel cancellation sound that cancels rear wheel vibration noise due to predicted rear wheel vibration at the position to be silenced on the basis of a rear wheel reference signal, and a turning state detection means which detects a turning state of a vehicle. When a difference in travel trajectory between a front wheel and a rear wheel is detected on the basis of the turning state, the cancellation sound output means suppresses the output of the rear wheel cancellation sound.

Abstract: An active noise control device detects composite vibration of a vibration transmitting route to which both vibration of a rotating body caused by generation or transmission of drive force of a vehicle and vibration of a wheel generated by contact between the wheel and a road surface are transmitted. A first reference signal for defining a reference waveform of a canceling sound for canceling vibration noise in a vehicle interior is generated based on the composite vibration. The component of the canceling sound for canceling vibration noise of the rotating body is removed from the first reference signal to generate a second reference signal for defining a reference waveform of the canceling sound for canceling vibration noise of the wheel. The canceling sound is outputted based on the second reference signal.

Abstract: Speech from a driver and speech from a passenger in a vehicle is selected directionally using a plurality of directional microphones. Sounds detected as coming from a passenger from a plurality of directional microphones are suppressed from sounds detected as coming from a driver by a second plurality of directional microphones.

Abstract: A system for controlling vehicle interior sound using a smart phone and a method thereof include a driving information provider to provide driving information while a vehicle is being driven. A smart phone includes a microphone which senses interior noise or sound of the vehicle and generates a sound control signal to diminish or amplify the interior noise based on the driving information from the driving information provider. An audio amplifier amplifies the sound control signal received from the smart phone and outputs an amplified signal though a speaker.

Abstract: An active noise control system for exhaust systems of a combustion engine operated vehicle comprises an anti-sound control connectable to an engine control of the vehicle and a loudspeaker connected to the control for receiving control signals and designed for generating an anti-sound in a sound generator, fluidically connectable to the exhaust system. In the control, at least two curves are stored in order to cancel airborne sound conducted in the exhaust system through outputting the signal to the loudspeaker. The curves cover different temperature ranges of the exhaust gas, which temperature ranges overlap one another by pairs or directly adjoin one another. The control is furthermore designed to select a curve suitable for a respective temperature of the exhaust gas conducted in the exhaust system from the available curves by means of signals output by the engine control and output signals to the loudspeaker making use of this curve.

Abstract: A noise control device includes the following structural elements. A signal memory records both of a noise signal supplied from a noise microphone and an error signal supplied from an error microphone. A filter coefficient calculator calculates a fixed filter coefficient of a control filter by using data recorded in the signal memory. A filter coefficient renewing section renews, at a given timing, a filter coefficient set at a fixed filter in a control filter to a filter coefficient read out from the filter coefficient calculator.

Abstract: A personal safety system detects imminent danger or other event of interest and then modifies a sound panorama to focus a user's attention towards the direction of the danger or other event of interest. The personal safety system may isolate sounds originating from the direction of the danger or other event of interest, collapse the sound panorama towards the direction of the danger or other event of interest, or compress the sound panorama to align with the direction of the danger or other event of interest. The personal safety system may be integrated into an automobile or a wearable system physically attached to the user. Advantageously, the attention of the user may be drawn towards imminent danger or other events of interest without introducing additional sensory information to the user, thereby reducing the likelihood of startling or distracting the user.

Abstract: A reference signal generating unit of an active-noise-reduction device of the present invention outputs a referencing signal having a correlation with a vibration to an adaptive filter unit. A filter coefficient update unit receives an input of an error signal, and successively updates a filter coefficient of the adaptive filter unit. The error signal is generated by a cancelling sound based on the output of the adaptive filter unit and noise. The detection unit detects a filter coefficient of the filter coefficient update unit, and determines a size of the output of the adaptive filter unit. Then, the amplitude of the cancelling sound is adjusted based on the size of the output of the adaptive filter unit estimated by the detection unit.

Abstract: Provided are methods and systems for noise suppression within multiple time-frequency points of spectral representations. A multi-feature cluster tracker is used to track signal and noise sources and to predict signal versus noise dominance at each time-frequency point. Multiple features, such as binaural and monaural features, may be used for these purposes. A Gaussian mixture model (GMM) is developed and, in some embodiments, dynamically updated for distinguishing signal from noise and performing mask-based noise reduction. Each frequency band may use a different GMM or share a GMM with other frequency bands. A GMM may be combined from two models, with one trained to model time-frequency points in which the target dominates and another trained to model time-frequency points in which the noise dominates. Dynamic updates of a GMM may be performed using an expectation-maximization algorithm in an unsupervised fashion.

Abstract: A method and device are presented for identifying machines, such as vehicles, based on acoustic machine signatures. An acoustic sensor generates machine-acoustic data about the machine. A machine-signature identifier receives the machine-acoustic data, determines a machine signature from the machine-acoustic data, and identifies the machine based on the machine signature. A machine-signature database, configured to store multiple machine signatures and/or machine-signature templates, may receive and process queries about machine signatures for machine identification. The machine-signature identifier may generate and send an instruction based on the identified machine. The instruction may instruct application of electronic countermeasures or may permit a vehicle to enter a secured area. An acoustic modulator may generate the machine-acoustic data to act as a machine signature. The acoustic modulator may generate the machine signature using an ultrasonic carrier.

Abstract: A device and method that is configured to operate an active noise reduction system for a motor vehicle, where there is an active noise reduction system input signal that is related to the vehicle engine speed, and where the active noise reduction system comprises one or more adaptive filters that use a filter coefficient to modify the amplitude and/or phase of a noise cancellation reference signal and output noise reduction signals that are used to drive one or more transducers with their outputs directed to reduce engine noise, where the value of the coefficient is related to an adaptive filter leakage factor. Changes in the engine speed, based on the input signal that is related to the vehicle engine operation, are monitored. In response to changes in the engine speed, the adaptive filter leakage factor is temporarily modified.

Abstract: A personal audio device, such as a wireless telephone, includes noise canceling circuit that adaptively generates an anti-noise signal from a reference microphone signal and injects the anti-noise signal into the speaker or other transducer output to cause cancellation of ambient audio sounds. An error microphone may also be provided proximate the speaker to estimate an electro-acoustical path from the noise canceling circuit through the transducer. A processing circuit uses the reference and/or error microphone, optionally along with a microphone provided for capturing near-end speech, to determine whether one of the reference or error microphones is obstructed by comparing their received signal content and takes action to avoid generation of erroneous anti-noise.

Abstract: An active noise control apparatus for an intake system of a vehicle may include a filter mounted on a portion of the intake system for blocking foreign materials; and a speaker assembly detachably installed at the portion to which the filter is mounted.

Abstract: A sound generator 103 for an anti-noise system for influencing sound waves propagating in exhaust systems or intake systems of vehicles driven by an internal combustion engine includes a loudspeaker basket 123, a membrane 122 supported by the loudspeaker basket 123, a permanent magnet 121 supported by the loudspeaker basket 123, a voice coil 126 supported by a voice coil carrier 125 and a membrane stop 150. The voice coil 126 is located within a constant magnetic field generated by the permanent magnet 121. The voice coil carrier 125 is supported by the membrane 122. The membrane stop 150 is located on the loudspeaker basket 123 adjacent to the membrane 122. The membrane stop 150 includes a projection 151 extending towards the membrane 122. An anti-noise system using the sound generator and a vehicle using the anti-noise system are also provided.

Abstract: A Noise Cancellation Process for enclosed cabins is disclosed. According to one embodiment, an input audio source corresponding to sound received from multiple microphones situated equidistantly in both directions in a two dimensional plane, is converted to a digital signal via an analog to digital (A/D) convertor. The A/D converted audio is analyzed for content to identify ambient noise. The frequency, amplitude and phase of the identified ambient noise is subsequently determined. A Noise correction sound wave is generated with negative phase of that corresponding to the identified ambient noise. The noise correction sound wave is added to the identified noise to create a noise corrected sound.

Abstract: Methods and systems for optimizing and audio communication system, including detecting a surrounding noise profile, determining one or more states of one or more noise-related conditions corresponding to the surrounding noise profile, and associating the one or more states of the one or more noise-related conditions to the surrounding noise profile.

Abstract: A system and method for reducing harmonic noise caused by two or more noise sources by causing one or more loudspeakers to produce sounds that are at about the same frequencies as the noise and of substantially opposite phase. There is a noise canceller associated with each noise source. Each noise canceller includes a harmonic sine wave generator that generates an output sine wave. Each noise canceller also has an adaptive filter that uses a sine wave to create a noise reduction signal that is used to drive one or more transducers with their outputs directed to reduce noise caused by the noise sources. There is an overlap detector that compares the harmonic frequencies and, based on their proximity, alters the operation of one or more adaptive filters.

Abstract: An anti-noise system for influencing exhaust noises propagating through a multi-flow exhaust system includes a controller 80 and at least one actuator. The at least one actuator is disposed in a sound generator 20; 21; 23; 25; 27, connected to the controller 80 for receiving control signals, and adapted to generate sound inside the sound generator 20; 21; 23; 25; 27. The sound generator 20; 21; 23; 25; 27 is connectable to at least two exhaust tracts 60, 61 of the multi-flow exhaust system of the vehicle simultaneously. The controller 80 is configured to generate a control signal that prompts the at least one actuator disposed in the sound generator 20; 21; 23; 25; 27 to cancel sound inside the at least two exhaust tracts 60, 61 of the vehicle's multi-flow exhaust system at least in part and preferably completely.

Abstract: Provided is an active noise cancellation apparatus capable of reliably reducing road noise by reducing vibration of a vehicle component part which generates road noise by using a vibration generator. A plurality of reference signal detectors are placed respectively on right and left knuckles for respectively supporting right and left wheels. A vibration generator and an error signal detector are placed on a vehicle component part. A controller performs respective adaptive controls based on each of reference signals and an error signal so as to reduce the error signal, and controls the vibration generator based on a sum of respective output values of the adaptive controls.

Abstract: A canalphone system may include a canalphone housing, and a first high frequency driver carried within the canalphone housing. The system may also include a second high frequency driver carried within the canalphone housing where the second high frequency driver is tuned with the first high frequency driver to deliver lower distortion than a standard canalphone high frequency driver and/or lower distortion than two standard canalphone high frequency drivers that are not tuned with each other.

Abstract: An active vibration noise control device having a pair of speakers, including: a basic signal generating unit generating a basic signal based on a vibration noise frequency; an adaptive notch filter generating a first control signal provided to one speaker using a first filter coefficient and generating a second control signal provided to the other speaker using a second filter coefficient to cancel the generated vibration noise; a microphone detecting cancellation error between the vibration noise and the control sounds and outputting an error signal; a reference signal generating unit generating a reference signal based on a transfer function from the speakers to the microphone; a filter coefficient updating unit updating first and second filter coefficients, minimize the error signal; and a phase difference limiting unit limiting a phase difference between control sounds generated by different speakers. Therefore, it becomes possible to appropriately ensure a uniform and wide noise-cancelled area.

Abstract: A sound generator for influencing sound waves propagating in exhaust or intake systems of combustion engine driven vehicles includes: an enclosure having a port opening for communication with an exhaust and/or intake system; a loudspeaker basket supported by the enclosure; a membrane and a permanent magnet supported by the loudspeaker basket; and a voice coil supported by a voice coil carrier. The voice coil is disposed in a constant magnetic field created by the permanent magnet and is connected to the membrane. The membrane is located between the port opening and the permanent magnet. The membrane is funnel-like or dome-like, with the top or top face of the funnel-like membrane or the geometric center of the dome-like membrane facing away from the permanent magnet. An anti-noise system using the sound generator, and a vehicle using the anti-noise system are also provided.

Abstract: A sound generator is provided capable of generating vehicle sound that will be produced when a specific sound element is changed out of a plurality of sound elements arising from the operation of a plurality of components mounted on a vehicle.

Abstract: A system (7), for influencing noises of a vehicle, includes a controller (9) and at least one connected loudspeaker (2) that generates noise inside a sound generator (3) in response to a control signal. The controller includes a microprocessor (91; 91?), a digital-to-analog converter (92), an amplifier (93), and a step-up converter (97). The microprocessor generates a digital control signal, to generate a noise to cancel noise inside an exhaust system and/or an intake system and/or to generate a noise inside an engine compartment. The digital control signal is converted by the digital-to-analog converter into an analog control signal. The amplifier amplifies the analog control signal output from the digital-to-analog converter. The step-up converter is connected to an automobile battery (10) of the vehicle and converts a battery voltage (VBATT) supplied by the automobile battery to a constant value, with this output as a supply voltage (VB) to the amplifier.

Abstract: An active noise control (ANC) system may be implemented to both sides of a fan, such that both directions of the noise emitting are treated to reduce the overall noise. The impact on airflow is minimal, and the technique is very effective in a broad range of low frequencies. Passive sound-absorbing materials may be included for attenuation of high frequencies. The resulting quiet fan produces a low level of noise compared to any other device based on fan, which produces the same capacity of airflow. The quiet fan may be incorporated in any mechanical system which requires airflow induction such as: computers, air conditioners, machines, and more.

Abstract: A system, device and method that is configured to operate an active noise reduction system for a motor vehicle, where there is an adaptive feed-forward noise reduction system input sine wave at a frequency to be cancelled, and where the adaptive feed-forward noise reduction system includes an adaptive filter that outputs noise reduction signals that are used to drive one or more transducers with their outputs directed to reduce engine noise, and further includes an input transducer with an output signal that is a source of a control signal for the adaptive filter. The output signal of the input transducer is filtered before it reaches the adaptive filter so as to reduce the level of the output signal of the input transducer at one or more frequencies that are close to the frequency of the input sine wave.

Abstract: The invention relates to a method (30) for damping and/or amplifying a sound introduced into a passenger compartment (10) of a motor vehicle, in particular an electrically driven motor vehicle, said sound being generated (32) by a sound source (22) arranged outside of the passenger compartment (10). A correction signal is generated (40) by means of correction signal means (16) which are paired with the sound source (22) and/or a sound-transmitting structure (20) of the motor vehicle, and the correction signal is determined (38) such that the sound is introduced into the passenger compartment (10) in a damped or amplified state.

Abstract: A loudspeaker arrangement in a motor vehicle includes at least one loudspeaker, which is able to be driven by an audio processor, the loudspeaker being arranged as at least one electrostatic planar loudspeaker.

Abstract: Provided is an active vibration noise suppression apparatus having good robustness without determining a secondary transfer function while not performing adaptive control. A first control unit generates a control signal by a first adaptive algorithm as a direct adaptive algorithm. A storing unit stores an equivalent value Gh of a secondary transfer function G which is adaptively updated as an adaptive filter by the first control unit. A second control unit uses a second adaptive algorithm which uses the equivalent value Gh of the secondary transfer function G stored in the storing unit as a feedforward coefficient and updates a filter coefficient C2 of the control signal as an adaptive filter based on the feedforward coefficient. The second control unit generates the control signal by the second adaptive algorithm when the first control unit does not generate the control signal.

Abstract: An improved user experience is provided for passengers of a transportation vessel, such as an airplane. A passenger's experience is enhanced by allowing the passenger to enjoy media provided by an entertainment device without ambient noise. When the passenger requests accesses to a media item through the entertainment device, a microphone in the entertainment system generates an ambient noise signal based on captured ambient noise. A noise cancellation device generates a predictive noise cancelling signal based on the ambient noise signal. To generate the predictive noise cancelling signal, the noise cancellation device inverts the ambient noise signal and applies a predictive phase shift to the signal based on an estimated distance between the microphone and the passenger's ears. The noise cancelling signal is mixed with audio of the media item.

Abstract: A pedestrian alert system includes, a noise producing member having a primary acoustic output surface configured and disposed to direct noise from the noise producing member along a first axis, and at least one secondary acoustic output surface that allows noise to pass from the noise producing member along a second axis that is distinct from the first axis. An acoustic focusing member is provided about the noise producing member. The acoustic focusing member is configured and disposed to re-direct noise from the second axis toward the first axis.

Abstract: Systems and methods to cancel noise in a vehicle are disclosed. A first speaker is positioned forward of a steering wheel of a vehicle. The first speaker generates a first signal configured to acoustically cancel noise produced by operation of the vehicle. A second speaker is positioned forward of the steering wheel. The second speaker generates a second signal to acoustically cancel the noise produced by the operation of the vehicle. The first and the second speakers are capable of generating the first and the second signals independently of one another.

Abstract: An active noise reduction system using adaptive filters. A method of operation the active noise reduction system includes smoothing a stream of leakage factors. The frequency of a noise reduction signal may be related to the engine speed of an engine associated with the system within which the active noise reduction system is operated. The engine speed signal may be a high latency signal and may be obtained by the active noise reduction system over audio entertainment circuitry.

Abstract: A reverberation suppression device comprises: an echo canceller that removes an echo component included in an input signal; a howling suppressor that detects occurrence of howling based on a frequency characteristic of the input signal from which the echo component has been removed and attenuates a frequency level of a component of the detected howling; and an initial sound suppressor that detects a sound section of the input signal in which the frequency level of the howling component has been attenuated and suppresses a signal value at a sound start portion of the detected sound section.

Abstract: A device is provided for influencing the passenger compartment noise in a motor vehicle includes, but is not limited to a noise signal generator for generating an offsetting noise signal, which includes, but is not limited to a control input for receiving a control signal that is representative of the engine load of the motor vehicle, and a loudspeaker for receiving the offsetting noise signal and emitting an offsetting noise into the passenger compartment of the motor vehicle. The noise signal generator furthermore includes, but is not limited to an input for a temperature signal of a temperature sensor and is equipped to generate the offsetting noise signal as a function of a signaled temperature.

Abstract: It includes a microphone for detecting noise emitted from a noise source, a noise controller for generating control sound signal to reduce noise detected by the microphone based on information from the microphone, and a speaker for outputting control sound based on control sound signal from the noise controller, wherein a plurality of microphones and speakers are arranged for each seat, and a plurality of microphones are arranged in higher density for each seat in a specific direction.

Abstract: A method and apparatus for providing simultaneous enhancement of transmission loss and absorption coefficient using activated cavities is presented. A layer of material is provided, and a backing plate having a plurality of cavities on the top surface of said backing plate, is disposed adjacent a top surface of said layer of material. A screen is disposed along the top surface of said cavities on said backing plate and at least one cavity includes an actuator disposed within the cavity and a control system receiving a signal from the microphone and receiving a signal from the accelerometer and providing a drive signal to the actuator to provide an acoustic output to provide simultaneous insertion loss and absorption which serves to minimize a linear combination of the signal from the microphone and the signal from the accelerometer.

Abstract: A noise treatment device (D) comprising at least one local noise sound sensor (30) and at least one sound system having a support (11, 12) and at least one sound actuator (21, 22, 21?, 22?). The device also includes a position sensor for determining the position of a person's head, at least one treatment unit (40, 40?) connected to the local noise sound sensor to receive a local noise signal and configured to deliver a control signal to each sound actuator (21, 22, 21?, 22?), the control signal being a function of said local noise signal and of at least one transfer function per ear, and active matching means (70) co-operating with said position sensor in order to keep each transfer function used in preparing each control signal representative of the path to be traveled by said anti-noise.

Abstract: The present invention relates to a method for processing sound signals in a vehicle multimedia system. A sound signal is recorded by a microphone. A voice signal component resulting from reproducing a voice signal and an audio signal component resulting from reproducing an audio signal are compensated in the recorded sound signal. The invention further relates to a system for processing sound signals and a vehicle multimedia system.

Abstract: There is provided an entertainment system comprising at least one seat, an electronic unit (100) for active noise reduction in the seat and at least one headphone (300). The headphone has an electro-acoustic reproduction transducer (310), a microphone (330) for recording interference signals and an adjusting unit (320) having an active filter for correcting a frequency response characteristic of the output signal of the microphone, for performing pre-filtration for active noise reduction and for the output of a corrected and filtered signal. The electronic unit (100) performs active noise reduction based on the corrected and filtered signal of the adjusting unit (320).

Abstract: A method and a device for suppressing noise in the passenger compartment of a vehicle, which include at least one transducer, a programmable computer, at least one acoustic sensor, the computer being configured such as to apply an electro-acoustic model of the passenger compartment to a correcting system model including a central controller with fixed coefficients joined to a block of variable coefficients, including a Youla parameter in the form of a Youla block Q. The first phase includes determining and calculating the electro-acoustic model and the control law for at least one predetermined noise frequency. In a second phase, in real time, the computer applies the control law to the electro-acoustic model in accordance with the current frequency of the noise to be suppressed.

Abstract: A tunable, sound enhancing air induction system for an internal combustion engine includes an air supply duct extending between an air cleaner and a throttle body, and an acoustic amplifier mounted to the air supply duct at an anti-node of a desirable engine induction sound. The acoustic amplifier furnishes the desired sound to the passenger compartment of the vehicle, either through a duct, or by a directional horn.

Abstract: A noise suppression system includes plural microphones, a fixed beam former, a blocking matrix, plural adaptive filters, and a direction of arrival circuit coupled to the adaptive filters that prevents the filters from adapting in the presence of a signal in the look direction. The direction of arrival circuit causes the filters to adapt more quickly in the absence of a signal in the look direction. A pair of adjustable gain circuits is coupled to each microphone. A first adjustable gain circuit from each pair is calibrated during the presence of a desired signal and a second adjustable gain circuit from each pair is calibrated during the presence of an interfering signal. A fixed null-forming circuit is coupled to a first pair of variable gain circuits and an adaptive null forming circuit is coupled to a second pair of adjustable gain circuits. The ratio of the gains of the null forming circuits is used as a control signal.

Abstract: In an acoustic control system an operation range of an active type noise control device (an ANC device) and an operation range of an active type effect sound control device (an ASC device) are exchanged in accordance with the number of working cylinders of an engine.

Abstract: An acoustic management system configured to compensate for acoustical dampening is provided. The system includes a microphone configured to detect a first acoustic signal from an acoustic environment and a logic circuit. The logic circuit detects an onset of the acoustical dampening between the acoustic environment and the microphone. The logic circuit generates an acoustic damping compensation filter, which is applied to the first acoustic signal to generate a drive signal.

Abstract: An echo cancelling algorithm in a communication device initializes a step size value used in an adaptive echo filter based on a background noise signal power level relative to a power level of a received signal and a power level of an echo estimate relative to an output of an echo canceller. The algorithm then adjusts the step size value. One aspect adjusts the step size based on the detection of large fast fourier transform values at one, or more, disturbing-signal frequencies. Another aspect estimates residual echo energy to adjust an estimated echo energy, which then is used to set a double talk flag if a transmit signal has much more power than the estimated echo signal. Another aspect compares transmit signal power to a decimated version of the transmit signal power and sets the double talk flag if the former exceeds the latter by a predetermined amount.

Abstract: A rearview mirror system for a vehicle includes an interior rearview mirror assembly including a control. The interior rearview mirror assembly may include a video display device operable to display video information for viewing by a driver of the equipped vehicle through an electrochromic reflective element of the interior rearview mirror assembly. The control may include a digital signal processor disposed in the interior rearview mirror assembly. The interior rearview mirror assembly may include a vehicle bus node. When the interior rearview mirror assembly is mounted in the equipped vehicle, the vehicle bus node may be connected to a vehicle bus of the equipped vehicle, and at least one of (a) the control conveys signals to the vehicle bus via the vehicle bus node and (b) the vehicle bus conveys signals to the control via the vehicle bus node.

Abstract: Secure outsourced aggregation of data using one-way chains is discussed in this application. Each input data source such as a sensor generates a Verifiable Synopsis (“VS”) which includes sensor data, an Inflation Free Proof (“IFP”) generated using a cryptographic function and a Self-Authenticating Value (“SEAL”) chain generated using a one-way function. An aggregator takes a plurality VSs from multiple data sources and aggregates them together into one. Maximum value, top-k, count, count distinct, sum, average, and other aggregate functions may be used. Folded VS provides a concise proof that no value greater than the maximum value was reported by a sensor, thus providing a check against deflation of sensor data. Similarly, the cryptographic function of the IFP provides a mechanism to prevent inflation of the sensor data. Thus it becomes possible at a portal to verify that aggregated data has not been inflated or deflated by the aggregator.